No one we talked to wanted to go on the record about this topic. But privately, executives familiar with Facebook's ad business confirmed that the social network does indeed play favorites with its ad clients, alternately rewarding or punishing those it does or doesn't like.

To put this in context, in the media business, it's common for sellers to be extremely solicitous to their advertising clients. Dinners, drinks, and free tickets to sporting and arts events for buyers are the norm.

Generally, Facebook vice president of global marketing solutions Carolyn Everson has steered the company toward a policy of being more accommodating to the ad agencies and buyers who, after all, provide about 90 percent of the company's revenues. (Facebook declined to comment).

A source close to Facebook, however, said the reason the company requires its clients to adhere to its strict guidelines is to ensure that buyers are as well aligned as possible with Facebook so that campaigns get the best performance possible. Executives at Facebook have seen agencies put out press releases claiming they can use Facebook in ways "that are literally not possible," this source says. Facebook doesn't want clients to say "Facebook didn't work for us" when those campaigns inevitably fail. So the company tries to keep its agency clients on the same page.

Not all vendors get treated equally.

The new SPMD announcement was held with much fanfare at an event hosted by Saleforce's new Dreamforce unit (formerly Buddy Media), by Facebook's David Fischer, vp/advertising and global operations. It's not surprising that Vitrue, a competing company owned by Oracle, wasn't there — or even on the SPMD list. Nor was Syncapse, which also provides enterprise software for CRM and sales executives who use Facebook as a marketing tool. And nor was TBG Digital, which is one of Facebook's biggest ad buyers.

Wildfire didn't make the list either. (It's now owned by Google, which competes with Facebook for ad dollars.)

Why the differing treatment? Here's what we heard from our sources:

"They've got to keep people in line. They reward people who do good stuff and they punish people who do bad shit."